fix: prevent discuss-phase from ignoring workflow instructions (#1292)

The discuss-phase command file contained a 93-line detailed <process>
block that competed with the actual workflow file. The agent treated
this summary as complete instructions and never read the execution_context
files (discuss-phase.md, discuss-phase-assumptions.md, context.md template).

Root cause: Unlike execute-phase and plan-phase commands (which have short
2-line process blocks deferring to the workflow file), discuss-phase had
inline step-by-step instructions detailed enough to act on without reading
the referenced workflow files.

Changes:
- Replace discuss-phase command's <process> block with a short directive
  that forces reading the workflow file, matching execute-phase/plan-phase
  pattern
- Add MANDATORY instruction that execution_context files ARE the
  instructions, not optional reading
- Register workflow.research_before_questions and workflow.discuss_mode
  as valid config keys (were missing from VALID_CONFIG_KEYS)
- Fix config key mismatch: workflows referenced "research_questions"
  but documented key is "workflow.research_before_questions"
- Move research_before_questions from hooks section to workflow section
  in settings workflow
- Add research_before_questions default to config template and builder
- Add suggestion mapping for deprecated hooks.research_questions key
- Add 6 regression tests covering config keys and process block guard

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

get-shit-done/workflows/new-project.md

@@ -218,7 +218,7 @@ Ask inline (freeform, NOT AskUserQuestion):
 
 Wait for their response. This gives you the context needed to ask intelligent follow-up questions.
 
-**Research-before-questions mode:** Check if `research_questions` is enabled in `.planning/config.json` (or the config from init context). When enabled, before asking follow-up questions about a topic area:
+**Research-before-questions mode:** Check if `workflow.research_before_questions` is enabled in `.planning/config.json` (or the config from init context). When enabled, before asking follow-up questions about a topic area:
 
 1. Do a brief web search for best practices related to what the user described
 2. Mention key findings naturally as you ask questions (e.g., "Most projects like this use X — is that what you're thinking, or something different?")