build(packaging): align cargo binary identities

[sandersonstabo]

Dependency

• Stacked directly on feat(backend): add conversation commit notifier #333 (agent/backend-conversation-commit-notifier-port-55fdb03).

Scope

• Freeze the four approved Cargo binary output identities with a source-only acceptance test.
• Keep the stable launcher as ae.
• Rename the installer output from ae-installer to installer.
• Make the desktop and backend Cargo outputs explicit as editor and forge.
• Register the focused packaging test in package and root lint/format/test aggregates.

Exclusions

• Does not add the four Bazel binary targets; that is the next packaging packet.
• Does not assemble/install archives, alter versioned layout, sign artifacts, or change runtime behavior.
• Cargo package names remain internal crate identities.

Verification

Exact-head jobs=1 gate on 9c32c38bf0a4c88cedd6654b730a89bcbe844447:

• //tests/packaging:cargo_binary_identity_test build
• focused uncached test
• fresh direct Rust Clippy aspect
• //:format_test
• cargo metadata --locked --offline --no-deps
• exact seven-path hash/status guards
• Bazel shutdown exit 0

Receipt: D:/artisan-editor-gate-logs/portable-cargo-binary-identity-20260829-gate2/receipt.json.

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Summary by cubic

Aligns the four Cargo binary output identities so packaging no longer relies on Cargo defaults. The installer binary is renamed from ae-installer to installer, and the frontend and backend binaries are now explicit editor and forge; the launcher remains ae. Anything referencing ae-installer must update to installer.

Test coverage

• Adds a source-only test that parses each manifest's [[bin]] block and rejects ambiguous or invalid identities.
• Registers the test in the root lint, format, and test aggregates.

^{Written for commit 9c32c38. Summary will update on new commits.}