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).

apps/tui-go/internal/app/update.go

@@ -324,6 +324,10 @@ func (m Model) handleNormalKey(k keyMsg) (tea.Model, tea.Cmd) {
 		m.openGrants()
 	case "g":
 		m.openConfig()
+	case "P":
+		m.openProjectProfile()
+	case "O":
+		m.openOperatorProfile()
 	case "m":
 		m.openModelsOverlay()
 	case "w":
@@ -658,6 +662,13 @@ func (m Model) handleOverlayKey(k keyMsg) (tea.Model, tea.Cmd) {
 	if m.overlay == OverlayConfig {
 		return m.handleConfigKey(k)
 	}
+	// Project/operator profile overlays own all their keys, same reason as config.
+	if m.overlay == OverlayProjectProfile {
+		return m.handleProjectProfileKey(k)
+	}
+	if m.overlay == OverlayOperatorProfile {
+		return m.handleOperatorProfileKey(k)
+	}
 	// Sessions overlay owns all its keys: enter resumes (emits a cmd), so it can't
 	// share the generic no-cmd esc path below.
 	if m.overlay == OverlaySessions {