Fix analytics-review on workflow_dispatch: pass resolved PR context to the agent

Dry-run 32015295640 (PR #146) went green end-to-end after the v0.86.2
recompile, but the agent posted nothing: the resolve pre-step's
AW_PR_NUMBER/AW_HEAD_REF land in step env only, which never reaches the
agent sandbox, and on workflow_dispatch the event payload has no PR
object. The agent concluded "no associated pull request ... nothing to
review" and noop'd.

Fix 1: the resolve step (now id: resolve_pr) also writes step outputs
and /tmp/gh-aw/context/run-context.md — the context dir is the one
channel proven to reach the agent (it read jira-ticket.md in the same
run). The prompt body names run-context.md as the source of truth for
PR identity, treats a dispatch run with a resolved PR as a normal
review, and reserves noop for runs where no PR resolves at all.
(${{ steps.* }} interpolation into the body cannot work: the prompt is
rendered in the activation job, the steps run in the agent job.)

Fix 2: the same run showed "JIRA returned HTTP 404 for ENG-909" —
ambiguous, since JIRA answers 404 for missing ticket, missing project
permission, AND bad credentials. On any non-200 the step now probes
/rest/api/3/myself and writes an auth diagnosis into the marker
(credentials rejected vs authenticated-but-cannot-see vs unreachable),
reporting HTTP codes only, never credential values. Still never fails
the job.

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

Author: amjithtitus09