decide the dogfood agent model (D-83)

Records D-83 answering Gap 5 of docs/self-analysis.md: clide commits to
both "Claude inside clide" models, with the clide-HOSTED stream-json
session (D-77/D-78) as the PRIMARY dogfood target — the process clide
spawns, hence the one Epic B (T-214) bootstraps (CLIDE_SOCK/CLIDE_WORKSPACE
+ PATH + context note + Bash(clide *) allow rule). The EXTERNAL CLI driver
(D-68) stays a first-class but SECONDARY, best-effort integration: manual
install (T-212), no promise to observe its non-clide tool use.

Scopes the D-6 parity contract (Epic C / T-218) to clide's own surfaces
reflected through the CLI in both directions; an external agent's
side-channel reads/tests/git are explicitly out of parity scope.

Closes T-224 (under T-208 "Give Claude hands").

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

governance/README.md

@@ -124,6 +124,7 @@ You might also want, project-permitting:
 - [D-80: `files.read` allows trusted Claude config roots beyond the workspace](decisions/architecture.md#d-80-filesread-allows-trusted-claude-config-roots-beyond-the-workspace) — _architecture_
 - [D-81: Right-pane reader load is driven by a retained `ReaderNav`, not per-view state or bus retention](decisions/architecture.md#d-81-right-pane-reader-load-is-driven-by-a-retained-readernav-not-per-view-state-or-bus-retention) — _architecture_
 - [D-82: Keymap sequences are space-separated; matching is a reusable matcher consumed at the interception point](decisions/architecture.md#d-82-keymap-sequences-are-space-separated-matching-is-a-reusable-matcher-consumed-at-the-interception-point) — _architecture_
+- [D-83: Dogfood agent model — hosted stream-json session primary, external CLI driver secondary](decisions/architecture.md#d-83-dogfood-agent-model--hosted-stream-json-session-primary-external-cli-driver-secondary) — _architecture_
 
 ## Open questions