Wire staticcheck and deadcode, and gate both on a baseline (V-694)

The 2026-08-10 audit asked for three analyzers. V-682 wired the first as `make
vuln`. The other two were still absent: neither was installed on the box and no
target ran them, so every reachability claim in the audit stood unchecked.

`make lint` runs staticcheck v0.7.0 and `make deadcode` runs deadcode v0.48.0.
Both are pinned in the Makefile beside GO_VERSION and installed into deps/bin
the way govulncheck is, because a tool is not a dependency of the module. Both
carry the CGO env `test` carries, or the four CGO daemons fail to load and the
analyzer reports a build error instead of a finding. `make analyze` runs all
three. None joins `make test`: they install over the network and `test` has to
pass on a box with no route out.

Neither reports zero, so neither fails on its own output. staticcheck finds 20
and deadcode finds 13, and the audit asked for an allowlist by name, because
three of deadcode's eleven production symbols are deliberate and an unannotated
list invites deleting them. The accepted set lives in
scripts/analyzers/*.baseline, one line per finding with the reason it stays, and
scripts/analyzer-gate.sh gives the verdict. A key holds file, check id and
message, never a line number: a line number goes stale on the next edit above
it, and a gate that reports moved findings as new ones teaches the reader to
skip it. An entry whose finding is gone also fails, so a fix that leaves its
line behind does not pass.

deadcode runs with -test, because a test is a caller. Without the flag the
report is 172 lines, most of internal/router/eval, and none of it is a mistake.
With it, the 11 symbols the audit listed come back exactly, plus two test
helpers it did not count.

Three staticcheck findings were checked and are false positives, recorded as
such: the iCal determinism test must call RenderICal twice, the morning hedge
loop breaks after the first rune on purpose, and the SA9009 line is prose about
//go:embed with the real directive below it. One is V-687 already. The remaining
17 are V-701 with the judgement on each.

The analyzers caveat is deleted rather than edited. What replaces it is the
limit that is now true: the gates are green against a baseline, not against
zero.

Makefile

@@ -16,7 +16,7 @@ PIPER_BIN     := $(shell pwd)/deps/piper/piper
 PIPER_MODEL   := $(shell pwd)/models/tts/ru_RU-irina-medium.onnx
 PIPER_ESPEAK  := $(shell pwd)/deps/piper/espeak-ng-data
 
-.PHONY: t audit simulate stt-fixtures test-stt-golden all build build-stt build-tts build-daemon build-client build-waked build-web build-poll build-caldav clean test fmt-check vet run-stt run-tts run-web download-embedder deps-go deps-sentinel deps-vuln vuln tidy eval-router eval-reach eval-recall eval-phrasing eval-models build-gpud
+.PHONY: t audit simulate stt-fixtures test-stt-golden all build build-stt build-tts build-daemon build-client build-waked build-web build-poll build-caldav clean test fmt-check vet run-stt run-tts run-web download-embedder deps-go deps-sentinel deps-vuln vuln deps-lint lint deadcode analyze tidy eval-router eval-reach eval-recall eval-phrasing eval-models build-gpud
 
 all: build
 
@@ -119,6 +119,46 @@ vuln: deps-vuln
 	CGO_CFLAGS="$(CGO_CFLAGS)" CGO_LDFLAGS="$(CGO_LDFLAGS)" LD_LIBRARY_PATH="$(shell pwd)/deps/lib" \
 		PATH="$(shell pwd)/deps/go/go/bin:$$PATH" GOTOOLCHAIN=local $(GOVULNCHECK) ./...
 
+# lint and deadcode — the other two analyzers the 2026-08-10 audit asked for
+# (V-694). They are not part of `test` for the same reason `vuln` is not: they
+# install over the network, and they are slow enough that a change to one Go
+# file should not pay for them.
+#
+# Neither reports zero, so neither fails on its own output. The accepted set
+# lives in scripts/analyzers/*.baseline and scripts/analyzer-gate.sh decides.
+# What is new fails, and so does a baseline entry whose finding is gone.
+#
+# deadcode runs with -test, so a test file is a root. Without it the report is
+# 172 lines, most of internal/router/eval, and none of it is a mistake.
+STATICCHECK_VERSION := v0.7.0
+DEADCODE_VERSION    := v0.48.0
+STATICCHECK := $(shell pwd)/deps/bin/staticcheck
+DEADCODE    := $(shell pwd)/deps/bin/deadcode
+
+deps-lint: deps-sentinel
+	@mkdir -p deps/bin
+	GOTOOLCHAIN=local GOBIN=$(shell pwd)/deps/bin \
+		$(GO) install honnef.co/go/tools/cmd/staticcheck@$(STATICCHECK_VERSION)
+	GOTOOLCHAIN=local GOBIN=$(shell pwd)/deps/bin \
+		$(GO) install golang.org/x/tools/cmd/deadcode@$(DEADCODE_VERSION)
+
+# Both load the packages, so both carry the CGO env `test` carries. Without it
+# the four CGO daemons do not load and the analyzer reports a build error
+# instead of a finding -- which analyzer-gate.sh fails on rather than filters.
+ANALYZER_ENV = CGO_CFLAGS="$(CGO_CFLAGS)" CGO_LDFLAGS="$(CGO_LDFLAGS)" \
+	LD_LIBRARY_PATH="$(shell pwd)/deps/lib" \
+	PATH="$(shell pwd)/deps/go/go/bin:$$PATH" GOTOOLCHAIN=local
+
+lint: deps-lint
+	@$(ANALYZER_ENV) $(STATICCHECK) ./... | scripts/analyzer-gate.sh staticcheck
+
+deadcode: deps-lint
+	@$(ANALYZER_ENV) $(DEADCODE) -test ./... | scripts/analyzer-gate.sh deadcode
+
+# Every static gate in one command. Not `check`, because it is not the thing to
+# run before a commit: vuln reads the network and all three are slow.
+analyze: lint deadcode vuln
+
 # Run the tidy the sentinel makes possible. Not part of `test`: it rewrites
 # go.mod, and a build target that edits the module file is a surprise.
 # vendor/ is committed, so a tidy that drops a requirement must be followed by