fix(execenv): mandate comment-history read on assignment-triggered runs

GitHub #1839: when an issue is reassigned from agent A to agent B, B
often only reads the issue body and misses context A added in comments
(e.g. which repo to clone). The assignment-triggered workflow injected
into CLAUDE.md / AGENTS.md said "Read comments for additional context
or human instructions" — vague enough that agents routinely skipped
it. The comment-triggered branch already gives an explicit
`multica issue comment list` invocation, so behavior diverged.

Promote step 3 to a concrete CLI call, mark it mandatory, and surface
the most common failure mode (stale instructions on reassignment) so
the agent recognizes when it matters. Reorder so comments are read
*before* flipping status to `in_progress`, matching how a human would
catch up on a thread before claiming work.

server/internal/daemon/execenv/runtime_config.go

@@ -207,8 +207,9 @@ func buildMetaSkillContent(provider string, ctx TaskContextForEnv) string {
 		// Assignment-triggered: defer to agent Skills for workflow specifics.
 		b.WriteString("You are responsible for managing the issue status throughout your work.\n\n")
 		fmt.Fprintf(&b, "1. Run `multica issue get %s --output json` to understand your task\n", ctx.IssueID)
-		fmt.Fprintf(&b, "2. Run `multica issue status %s in_progress`\n", ctx.IssueID)
-		b.WriteString("3. Read comments for additional context or human instructions\n")
+		fmt.Fprintf(&b, "2. Run `multica issue comment list %s --output json` to read the full comment history — this is mandatory, not optional. Earlier comments often carry context the issue body lacks (e.g. which repo to work in, the prior agent's findings, the reason the issue was reassigned to you). Skipping this step is the most common cause of agents acting on stale or incomplete instructions.\n", ctx.IssueID)
+		fmt.Fprintf(&b, "   - If the output is very large or truncated, use pagination: `--limit 30` to get the latest 30 comments, or `--since <timestamp>` to fetch only recent ones\n")
+		fmt.Fprintf(&b, "3. Run `multica issue status %s in_progress`\n", ctx.IssueID)
 		b.WriteString("4. Follow your Skills and Agent Identity to complete the task (write code, investigate, etc.)\n")
 		fmt.Fprintf(&b, "5. **Post your final results as a comment — this step is mandatory**: `multica issue comment add %s --content \"...\"`. Your results are only visible to the user if posted via this CLI call; text in your terminal or run logs is NOT delivered.\n", ctx.IssueID)
 		fmt.Fprintf(&b, "6. When done, run `multica issue status %s in_review`\n", ctx.IssueID)