Resolve declared resource dependencies at request start (chat path)

[serguei-gorokhov]

Parent: #1930

What to build

A new enhancement-chain function, ResolveResourceDependenciesFn, runs for chat-completion calls to an application, before the per-request key is assigned — while the context still carries the originating user, so the reach checks evaluate the USER's permissions, not the app's (load-bearing timing, made loud by an assert).

Per declared record: resolve the target (current-user/… against the originating user's bucket, concrete global-view paths as-is), verify fresh against the user's reach, intersect with the content-bound admin-consent record, and bake the passing grants into the key the application will hold.

• Fail-closed per record: unreachable or unconsented targets simply do not grant; a required record that cannot resolve fails the call with an explicit 403 instead of the app half-working. Reach is all-or-nothing per record — no half-grants.
• Malformed records (config-file apps bypass write-time validation) are unresolvable — never a crash, never a grant; the read side re-enforces the write-side vocabulary (kind, READ/WRITE only).
• Runtime audit on the DIAL_RESOURCE_DEPS_AUDIT stream: one grant line per run, one denial line (unreachable or unconsented), one runtime-fail line when a required record rejects the call.
• Enforcement is unchanged — the existing per-request permission rule honors the grants, folder targets by prefix.

Smoke test proves the v1 happy path end to end: admin-authored app declares a personal prompts folder (current-user/prompts/dep-smoke/, write, required) → admin grants → user chats → the app's key writes inside the declared folder (200) and is refused outside it (403).

Acceptance criteria

• A declaring, admin-consented app called by a user who can reach the target: the PRK carries the grant; the app's subsequent resource call succeeds.
• Same app, user who cannot reach: no grant, no failure, denial audit line.
• required record failing reach/consent: the call fails with an explicit error + runtime-fail audit line.
• Apps without a section: bit-for-bit unchanged behavior.
• The timing assert exists and its test fails if the fn is wired after key assignment.

Blocked by

#1933

[serguei-gorokhov]

Implemented by #1943 (one PR of the stacked series publishing this feature; the PR's base is the previous story's branch — see the epic for the stack order).