docs: adapt SDD process + agent specs for alkgit

- sdd_process.md: alkcall -> alkgit
- coordinator: spawn prompt targets alkgit, constraints point at AGENTS.md
- implementation-specialist: conventions rewritten for the git-server
  workspace (replaces alkcall-specific vendored-types/BAST/abort items)
- code-reviewer: thiserror (no anyhow), sha256/acme feature flags
- architect/architecture-reviewer: examples de-alknetted

Verified: none needed (markdown only)

.opencode/agents/architect.md

@@ -326,10 +326,10 @@ result, a concrete use case to arrive.
 
 A decision should be `deferred(scope)` when:
 
-- The use case isn't concrete (e.g., "we don't know what the agent crate
+- The use case isn't concrete (e.g., "we don't know what the admin API
   will need from the call protocol")
 - The options depend on something that doesn't exist yet (e.g.,
-  "depends on the alknet-http crate spec")
+  "depends on the alkgit-http streaming adapter shape")
 - The trade-off requires data that can only come from implementation
   (e.g., "need performance benchmarks to choose between X and Y")
 - The decision is genuinely not needed for the current scope (e.g., "the
@@ -373,13 +373,14 @@ A decision should be `deferred(unclear)` when:
    (implies it's decided).
 2. **State the blocking condition** (`deferred(scope)`) or
    **investigation target** (`deferred(unclear)`) — what specific thing
-   would unblock this? Be concrete: "blocked on: alknet-agent crate spec
-   exists" or "investigation: work through 2+ example outbound-dial use
-   cases (hub→worker, worker→hub) to see how verifier-selection +
-   provider + connector compose."
+   would unblock this? Be concrete: "blocked on: alkgit-admin crate spec
+   exists" or "investigation: work through 2+ example git-over-ssh use
+   cases (clone and push) to see how identity + repo resolution +
+   pkt-line session compose."
 3. **State the impacts** — what does this block downstream? Be
-   specific: "blocks the first hub deployment because the hub dials
-   workers" not "blocks the hub crate." This is the triage signal that
+   specific: "blocks the http endpoint because receive-pack needs
+   unbuffered POST ingestion" not "blocks the http crate." This is the
+   triage signal that
    makes the deferral's urgency visible. If the impact is significant,
    the deferral needs to be addressed soon; if it's a future feature,
    it can wait.