Say on the card when a project's own file was ignored

An unknown field discards the whole declaration rather than the key it
did not recognise, so a machine that takes a project's commit before it
takes a dev-updater that understands it loses that project's components,
strip, staleWhen and resources at once. Nothing looks broken afterwards:
the card becomes a project that declares nothing, which is the ordinary
case, and the only thing saying otherwise was a line in this server's log
on a machine the person holding the phone cannot read.

project_config now answers a ProjectFile carrying the parse error beside
the declaration, and AppEntry::declaration_state returns both halves from
one read -- the manifest wants both, and the file is on that path. The
card draws its own sentence about what it means and what to do, then the
parser's own words, which name the file, the position and the offending
field; that half is selectable, since the fix happens on the other
machine.

Nothing is blocked by it. What was already accepted is what runs, so an
unrelated typo cannot stop a project that was working -- asserted in the
test, along with the error naming both the field and the file.

Seen on the emulator both ways: a project whose file gained a field from
the future says so under its action row, and the whole message goes when
the file parses again.

Raised by the tdep-survey session after its alsoWatch commit hit exactly
this against the older binary running here.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

AGENTS.md

@@ -255,6 +255,26 @@ mutable at runtime from the phone.
   that silence. It is part of the acceptance gate like every other
   declared field -- `same_declaration` destructures exhaustively, which is
   what forced the decision when the field was added.
+- **A declaration that cannot be read says so on the card.** RON's
+  `deny_unknown_fields` discards the *whole* declaration rather than the
+  key it did not recognise, so a machine that takes a project's commit
+  before it takes a dev-updater new enough to understand it loses that
+  project's components, `strip`, `staleWhen` and resources at once -- and
+  the card does not look broken, it looks like a project that declares
+  nothing, which is the ordinary case. That was the only difference
+  between the two states: a line in this server's log, on a machine the
+  person holding the phone cannot read. `config::project_config` now
+  answers a `ProjectFile` carrying the parse error beside the
+  declaration, `AppEntry::declaration_state` returns both halves from one
+  read (the manifest wants both, and the file is on that path), and the
+  card draws its own sentence about what it means followed by the
+  parser's own words -- selectable, since the fix happens on the other
+  machine. Nothing is *blocked* by it: what was already accepted is what
+  runs, so an unrelated typo cannot stop a project that was working.
+  Worst on the self entry, where `reconcile_self` derives the row from
+  that file at every startup: unreadable, and this server's own card
+  silently loses its server component and its build commands rather than
+  merely stopping noticing changes.
 - **The debug keystore is not `~/.android/debug.keystore`** -- that is the
   last of five places, and `sdk::android_prefs_dirs` resolves it the way
   AGP does, because the only thing that makes it the right key is being