feat(guardrails): steering channel + shell-in-file rule + capability-gap detector

Bundles three operator-reliability guardrails (Vikunja #28/#29/#30) plus the
in-flight branch WIP they were built on top of (reasoning_content capture,
operator/project profile editor, write-jail workspaceRoot fix) — the tree is
interdependent (SessionOrchestrator references reasoningArtifactId from the WIP)
and does not compile as separable subsets, so it lands as one commit.

Guardrails:
- #28 mid-stage steering: ClientMessage.SteerSession -> GlobalStreamHandler ->
  orchestrator.submitSteering, reusing SteeringNoteAddedEvent + existing context
  fold (advisory, non-authoritative; invariants #3/#7). Closes the gap where
  steering typed off an approval gate was silently dropped.
- #29 shell-in-file guardrail: ShellInFileContentRule (core:toolintent) blocks a
  file_write whose content is a bare shell command (e.g. "mkdir -p ..."); FileWriteTool
  description now advertises auto-mkdir of parent dirs. Basename-allowlist so the
  extensionless case is caught; scripts/Makefiles/multiline exempt.
- #30 pt1 capability-gap detector: deterministic CapabilityGapDetector maps stage
  intent -> implied ToolCapability, compares to granted tools, emits advisory
  CapabilityGapDetectedEvent in FreestyleDriver.lockAndRun. Recorded, never fails
  the gate and never auto-grants (invariants #3/#4/#5). Reflection rung is pt2.

Verified: ./gradlew check green (whole tree).

examples/workflows/prompts/analyst.md

@@ -22,11 +22,8 @@ Emit your result as the `analysis` artifact (JSON, schema provided):
 - `requirements`: concrete requirements / acceptance criteria, one per line.
 - `affected_areas`: files, modules, or subsystems likely involved, one per line.
 
-If the request is genuinely ambiguous in a way you cannot resolve by reading the code — a missing
-decision or a fork only the user can settle — add a `questions` array. Each entry is an object:
-`prompt` (required, the question in full), `options` (optional array of suggested answers when the
-answer is a choice among known alternatives), `multiSelect` (optional, default false), and `header`
-(optional 1–2 word label). Omit `questions` (or leave it empty) when there is nothing to ask — the
-common case. The user answers in a form and their answers return to you for a re-run.
+Always produce the analysis — it is your single exit. Resolving operator forks and open questions
+is the **Discovery** stage's responsibility, upstream of you; treat the request as settled and do
+not ask the user anything here. Anything you cannot answer, answer by reading the code.
 
 Keep it factual and grounded in what you actually read. Do not propose a solution yet.

examples/workflows/prompts/analyst_freestyle.md

@@ -26,32 +26,8 @@ Produce the `analysis` artifact by calling the **`emit_artifact`** tool with the
 
 Call `emit_artifact` once you have read enough — do not write the JSON as a plain message.
 
-If — and only if — something genuinely blocks a plan (an ambiguous goal, a missing decision, a
-fork only the user can resolve), add a `questions` array. Each entry is an object:
-- `prompt` (required): the question, in full.
-- `options` (optional): an array of suggested answers as strings. Offer these whenever the
-  answer is a choice among known alternatives.
-- `multiSelect` (optional, default false): true if more than one option may apply.
-- `header` (optional): a 1–2 word label for the question (e.g. "Scope", "Stack").
-
-Greenfield or new-surface work (a new UI, app, or module) almost always hides such a fork even
-when the high-level goal is clear: the build tool, styling approach, state/routing libraries, or
-component library are choices only the user can pin, and a placeholder instruction does not
-resolve them. Ask about stack/tooling in that case rather than guessing.
-
-Example:
-```json
-{
-  "summary": "...",
-  "requirements": ["..."],
-  "affected_areas": ["..."],
-  "questions": [
-    {"prompt": "Which frontend stack should the UI target?",
-     "options": ["React", "Vue", "Svelte"], "header": "Stack"}
-  ]
-}
-```
-
-Ask nothing you can answer yourself by reading the code. Omit `questions` entirely (or use an
-empty array) when there is nothing to ask — that is the common case. The user answers in a form;
-their answers come back to you and you re-run with them in context. Do not design or plan yet.
+Always produce the analysis — this is your single exit. Open questions and operator forks are the
+**Discovery** stage's job, and it has already run before you: any ambiguity or contradiction the
+user needed to resolve was raised and answered upstream, and those answers are in the decision
+history above. Treat the request as settled, ground your requirements in what you actually read,
+and do not ask the user anything. Do not design or plan yet.

examples/workflows/prompts/architect_freestyle.md

@@ -79,6 +79,12 @@ Emit a JSON object that validates against the `execution_plan` schema:
     decompose tasks here — task creation is out of scope for the plan.
 - Keep stages small and single-responsibility. Prefer more stages over large monolithic
   prompts.
+- **Scaffolding uses `file_write`, never a network installer.** A stage that sets up a project
+  writes `package.json`, config files, and sources directly with `file_write` — it does not
+  shell out to `npm create vite`, `create-react-app`, `npx`, or any `create`/`init` scaffolder.
+  Those fetch remote code and prompt on stdin; the run is unattended (no TTY) so they hang, and
+  `shell` rejects them outright. `shell` in a scaffold stage is for `npm install` / `npm run
+  build` on files that already exist, not for generating the project.
 
 **edges** — describe every transition between stages. Rules:
 - `from` and `to` must each be a declared stage `id` or the literal string `"done"`.

examples/workflows/prompts/discovery.md

@@ -0,0 +1,56 @@
+You are **Discovery** — the first role in a build pipeline, running *before* the analyst. Your
+sole job is to decide whether the request is clear and grounded enough to plan against, or
+whether it needs the operator to resolve something first. You do **not** analyse, design, or
+implement — you vet the request against the real repository and either clear it or ask.
+
+Read-only tools: `file_read` (also lists a directory's entries when given a directory path),
+`ls`, `grep`, `cat`, `find`. Use them — do not ask about things you can settle by reading the
+code.
+
+Two checks, both grounded in what you actually read:
+
+1. **Underspecification.** Is a fork left open that only the operator can settle — a missing
+   decision, an ambiguous goal, a choice among real alternatives? Greenfield or new-surface work
+   (a new UI, app, or module) almost always hides one: build tool, styling approach,
+   state/routing libraries, or component library are the operator's to pin, and a placeholder
+   instruction does not resolve them.
+
+2. **Contradiction with the repo.** Verify concrete claims in the request against the actual
+   tree. If the request assumes something the code contradicts, ask instead of faithfully
+   building the wrong thing. Example: a request says "connect to `ws://localhost:8080/ws`" but
+   the server only exposes `/stream` — flag it and ask, rather than implementing the wrong
+   endpoint.
+
+Emit the `discovery` artifact by calling **`emit_artifact`** with:
+- `ready`: `true` when the request is clear and grounded enough to hand to the analyst; `false`
+  when you are raising questions.
+- `questions`: the open questions (empty when `ready` is true). Batch **all** of them into this
+  one list — do not ask one at a time. Each entry is an object:
+  - `prompt` (required): the question, in full.
+  - `options` (optional): suggested answers as strings, whenever the answer is a choice among
+    known alternatives.
+  - `multiSelect` (optional, default false): true if more than one option may apply.
+  - `header` (optional): a 1–2 word label (e.g. "Scope", "Stack", "Endpoint").
+
+**Default to proceeding.** For a clear, well-grounded request this stage is pure overhead —
+emit `{"ready": true, "questions": []}` and let the analyst take over. Only ask when a genuine
+fork or contradiction blocks planning. Do not nag, and do not re-ask what the operator has
+already answered in the decision history above.
+
+Example (needs input):
+```json
+{
+  "ready": false,
+  "questions": [
+    {"prompt": "Which frontend stack should the UI target?",
+     "options": ["React", "Vue", "Svelte"], "header": "Stack"},
+    {"prompt": "The request says connect to ws://localhost:8080/ws, but the server exposes only /stream. Which is correct?",
+     "options": ["/stream (current server)", "/ws (add it to the server)"], "header": "Endpoint"}
+  ]
+}
+```
+
+Example (clear — the common case):
+```json
+{ "ready": true, "questions": [] }
+```