feat(ultraplan-local): v1.6.0 — /ultraresearch-local deep research command

Add /ultraresearch-local for structured research combining local codebase
analysis with external knowledge via parallel agent swarms. Produces research
briefs with triangulation, confidence ratings, and source quality assessment.

New command: /ultraresearch-local with modes --quick, --local, --external, --fg.
New agents: research-orchestrator (opus), docs-researcher, community-researcher,
security-researcher, contrarian-researcher, gemini-bridge (all sonnet).
New template: research-brief-template.md.

Integration: --research flag in /ultraplan-local accepts pre-built research
briefs (up to 3), enriches the interview and exploration phases. Planning
orchestrator cross-references brief findings during synthesis.

Design principle: Context Engineering — right information to right agent at
right time. Research briefs are structured artifacts in the pipeline:
ultraresearch → brief → ultraplan --research → plan → ultraexecute.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

plugins/ultraplan-local/commands/ultraplan-local.md

@@ -49,7 +49,22 @@ Parse `$ARGUMENTS` for mode flags:
    Error: plan file not found: {path}
    ```
 
-6. Otherwise: the entire argument string is the task description.
+6. If arguments contain `--research `: extract file path(s) after `--research`.
+   Collect paths until encountering another `--` flag or a token that does not
+   look like a file path (no `/` or `.md` extension). Maximum 3 briefs.
+   Set **has_research_brief = true**. Validate each path exists — if any is
+   missing, report and stop:
+   ```
+   Error: research brief not found: {path}
+   ```
+   The `--research` flag can combine with other flags:
+   - `--research brief.md <task>` — default mode with research brief
+   - `--research brief.md --fg <task>` — foreground with research brief
+   - `--research brief.md --spec spec.md` — spec-driven with research brief
+   Remove `--research` and its paths from the argument string before
+   applying the other flag checks above.
+
+7. Otherwise: the entire argument string is the task description.
    Set **mode = default**.
 
 If no task description and no spec file, output usage and stop:
@@ -57,6 +72,7 @@ If no task description and no spec file, output usage and stop:
 ```
 Usage: /ultraplan-local <task description>
        /ultraplan-local --spec <path-to-spec.md>
+       /ultraplan-local --research <brief.md> [brief2.md] <task description>
        /ultraplan-local --fg <task description>
        /ultraplan-local --quick <task description>
        /ultraplan-local --export <pr|issue|markdown|headless> <plan-path>
@@ -65,14 +81,21 @@ Usage: /ultraplan-local <task description>
 Modes:
   default       Interview (interactive) → background planning → notify when done
   --spec        Skip interview, use provided spec → background planning
+  --research    Enrich planning with pre-built research brief(s) (up to 3)
   --fg          All phases in foreground (blocks session)
   --quick       Interview → plan directly (no agent swarm) → adversarial review
   --export      Generate shareable output from an existing plan (no new planning)
   --decompose   Split an existing plan into self-contained headless sessions
 
+  --research can combine with other flags:
+    --research brief.md <task>              Default mode + research context
+    --research brief.md --fg <task>         Foreground + research context
+    --research brief.md --spec spec.md      Spec-driven + research context
+
 Examples:
   /ultraplan-local Add user authentication with JWT tokens
   /ultraplan-local --spec .claude/ultraplan-spec-2026-04-05-jwt-auth.md
+  /ultraplan-local --research .claude/research/ultraresearch-2026-04-08-oauth2.md Implement OAuth2 auth
   /ultraplan-local --fg Refactor the database layer to use connection pooling
   /ultraplan-local --quick Add rate limiting to the API
   /ultraplan-local --export pr .claude/plans/ultraplan-2026-04-06-rate-limiting.md
@@ -235,6 +258,21 @@ Then **stop**. Do not continue to Phase 2 or any subsequent phase.
 
 **Skip this phase entirely if mode = spec-driven.** Proceed to Phase 3.
 
+### Research-enriched interview
+
+If **has_research_brief = true**: read each research brief file before starting the
+interview. Then adjust the interview:
+
+1. Tell the user: "I've read {N} research brief(s). The interview will focus on
+   decisions and implementation details — skipping topics already covered."
+2. Skip questions about technologies, patterns, or approaches already researched.
+3. Focus on: implementation preferences, non-functional requirements, scope decisions.
+4. Reference brief findings in questions where relevant:
+   > "The research brief found that {finding}. Does this affect your approach?"
+   > "The brief identified {risk}. Should the plan account for this?"
+
+If **has_research_brief = false**: proceed with the standard interview below.
+
 Use `AskUserQuestion` to interview the user about the task. Ask **one question at
 a time** — never dump all questions at once. Follow up based on answers.
 
@@ -312,6 +350,7 @@ Task: {task description}
 Mode: {default | spec | quick}
 Plan destination: .claude/plans/ultraplan-{YYYY-MM-DD}-{slug}.md
 Plugin root: ${CLAUDE_PLUGIN_ROOT}
+Research briefs: {path1, path2, ...}  ← include ONLY if has_research_brief = true
 
 Read the spec file and execute your full planning workflow.
 Write the plan to the destination path.