ci: check every repo-relative path resolves, not just doc pointers

mara on #3923: "any gate we add should not have false positives". This is
the gate, and the reason it can exist without a skip-list is the prose fix
in the previous commit -- every false positive this arm would have raised
was a sentence naming where something used to live.

A third arm on the existing doc-pointer lint rather than a fourth CI job:
it inherits the job that already runs on every PR and in pre-push, the
`lint:allow` hatch the sibling arms honour, and the ::error annotation
format. A new job is a thing that can ship without ever running.

Scope is any repo-relative source path, not only `docs/**.md`. A comment
naming a moved .rs or .nix file misleads exactly as much as a dead doc
link, and nothing was checking it: 1123 such paths resolve on this tree
and none were verified before now.

Both ends of the pattern are anchored, each because its absence invented a
path -- an unanchored extension matched the prefix of a longer one, and an
unanchored prefix matched mid-path inside a nested directory, conjuring a
top-level twin of a real file. Those failures now surface as dead paths and
fail the build rather than passing silently, so they need no separate
control.

Written with placeholders, because the first draft named the two phantom
paths literally and the new arm immediately reported the script to itself.
The header already warned about exactly that, two lines above where I put
them.

Refs #3923

docs/agent-lifecycle/agent-hierarchy.md

@@ -155,11 +155,9 @@ Manager}` switch picks the MCP tool allow-list claude sees. Both are
   ancestor/descendant check instead of a manager-name check — see the
   module docs for `loose_ends.rs`, `stores/broker.rs`, `actions.rs`,
   and `workers/crash_watch.rs` for the current owner-check logic in
-  each. (Question/answer routing and its own manager-override cancel
-  path — formerly `hive-c0re/src/questions.rs` and
-  `stores/operator_questions.rs` — has been removed entirely; reminder
-  cancellation is now handled fully in-agent, see the note on
-  `CancelLooseEndKind::Reminder` in `hive-c0re/src/socket_server/mod.rs`.)
+  each. (Reminder cancellation is handled fully in-agent — see the note
+  on `CancelLooseEndKind::Reminder` in
+  `hive-c0re/src/socket_server/mod.rs`.)
 
 None of the above is a stable interface — treat the module doc
 comments as the source of truth for exactly which checks exist today.

docs/process/gotchas.md

@@ -472,7 +472,7 @@ Pipeline:
 - CommonMark from `nixosOptionsDoc.optionsCommonMark` is the only
   output — the source of truth, emitted as `.md`.
 - **HTML + CSS is rendered downstream by the website repo**
-  (`nix/options.nix` there), which consumes this bundle's `host.md` /
+  (its own `options.nix`), which consumes this bundle's `host.md` /
   `agent.md`, renders them with `cmark-gfm`, and shares one
   stylesheet (`docs.css`) across `/options/` and the prose `/docs/`
   tree. Keeping rendering in the website means the theme has a single

hive-agent/src/term_msg.rs

@@ -10,14 +10,12 @@
 //! `stream-json` line) can expand to several: an `assistant` message with
 //! both a text block and a `tool_use` block produces two rows.
 //!
-//! Design history: mara's terminal-message redesign (six rounds of
-//! negotiation on the forge) collapsed what was an 11-field frontend-side
-//! row shape (`StreamRow`, `frontend/packages/agent/src/lib/streamRow.ts`)
-//! plus raw claude-JSON passthrough into this 6-field shape, with
-//! classification moved server-side so the client-side `classifyEvent.ts` —
-//! a large per-tool dispatch table — mostly goes away. `kind`, `unread`,
-//! `from`, and `expanded_default` were all considered and dropped along the
-//! way; `level` replaces free-text CSS-class styling.
+//! Six fields, and classification belongs **here**, not in the client: the
+//! web UI renders what it is handed and owns no per-tool dispatch table, so
+//! a new tool needs no frontend change. `level` carries styling, so a row
+//! never names a CSS class. `kind`, `unread`, `from` and `expanded_default`
+//! are deliberately absent — adding one back is a design change, not an
+//! oversight.
 
 use serde::Serialize;
 use std::collections::HashMap;

scripts/check-doc-refs.sh

@@ -9,12 +9,18 @@
 # Emits a CI error annotation per hit and exits 1 if any pointer is dead, 0
 # otherwise. Runs as its own job; seconds, pure git+grep.
 #
-# Two arms, because a pointer is written two ways:
+# Three arms, because a pointer is written three ways:
 #   root — a repo-root-relative path in prose or a comment, `docs/<dir>/<f>.md`
 #   rel  — a markdown link resolved against the linking file, [x](../<dir>/<f>.md)
+#   path — any repo-relative source path, `<crate>/src/<f>.rs`, `nix/<f>.nix`
 # (spelled with placeholders on purpose: a literal example path here would be
 # a dead pointer this script then reports against itself)
 #
+# The third arm carries no skip-list, and could only be built after the prose
+# it would have flagged was fixed: every false positive was a sentence naming
+# where something *used to* live. Tolerating those needs a past-tense
+# heuristic — the permanent carve-out that teaches readers to ignore a gate.
+#
 # Scope is every tracked file, deliberately unrestricted by type: prose
 # describes a path in words, and a stale path in a config file (an ignore
 # rule, a build input) is a live defect rather than a stale comment.
@@ -98,10 +104,45 @@ done < "$tmp/rel"
 # something that resolves before a clean run means anything: if a rename, a
 # pattern edit or a tree move silences the search, that is a failure of this
 # script, not a property of the tree.
+# Third arm: repo-relative paths to any tracked file, not just `docs/**.md`.
+# A comment naming a moved `.rs` or `.nix` file misleads exactly as much as a
+# dead doc link, and nothing was checking it.
+#
+# Both ends are anchored, and each anchor is there because its absence
+# invented a path: unanchored, a `.js` extension matched the prefix of a
+# `.json` one, and a bare `<dir>/` matched mid-path inside `nix/<dir>/…`,
+# conjuring a top-level twin of a real nested file. (Placeholders, per the
+# header — a literal here would be a dead path this arm reports against
+# itself.) `grep -o` has no lookaround, so the boundary char is stripped below.
+prefix_pattern='(nix|scripts|docs|frontend|branding|hive-[a-z0-9-]+/src|hivectl/src|swarmctl/src|swarm-controller/src)'
+ext_pattern='(nix|sh|rs|md|ts|tsx|js|css|toml)'
+path_pattern="(^|[^A-Za-z0-9._/-])${prefix_pattern}/[A-Za-z0-9._/-]+\\.${ext_pattern}($|[^A-Za-z0-9])"
+
+git ls-files -z | xargs -0 -r grep -nEo "$path_pattern" /dev/null 2>/dev/null \
+  > "$tmp/paths0" || true
+sed -E 's/^([^:]*:[0-9]+:)[^A-Za-z0-9]?/\1/; s/[^A-Za-z0-9]$//' "$tmp/paths0" \
+  > "$tmp/paths" || true
+
+while IFS=: read -r file lineno ref; do
+  [ -n "${ref:-}" ] || continue
+  exempt "$file" "$lineno" && continue
+  if [ -f "$ref" ]; then
+    alive=$((alive + 1))
+  else
+    dead=$((dead + 1))
+    printf '::error file=%s,line=%s::repo path does not resolve: %s\n' \
+      "$file" "$lineno" "$ref"
+  fi
+done < "$tmp/paths"
+
 if [ "$(wc -l < "$tmp/root")" -eq 0 ]; then
   echo 'check-doc-refs: root-pointer search matched nothing — pattern or tree changed' >&2
   exit 1
 fi
+if [ "$(wc -l < "$tmp/paths")" -eq 0 ]; then
+  echo 'check-doc-refs: repo-path search matched nothing — pattern or tree changed' >&2
+  exit 1
+fi
 if [ "$(wc -l < "$tmp/rel")" -eq 0 ]; then
   echo 'check-doc-refs: relative-link search matched nothing — pattern or tree changed' >&2
   exit 1