docs(sprint-5): add Sprint 5 prompts, slash commands and closures skill

[kwakker35]

Lay down the Sprint 5 planning corpus for the functions/closures work:

• prompts/sprint-5: kickoff and QA prompts; archived per-increment prompts (A-F) mirrored into .claude/commands as sprint-5-* slash commands
• .claude/skills/emitting-closures-and-upvalues: the four-category variable resolution and open/closed upvalue lifecycle procedure for Increment D
• .claude/agents/grob-closure-specialist: Opus-pinned specialist for the upvalue-lifetime sub-problem
• docs/design/_pending/D-318-drop-in: named-argument call-site diagnostics (E0008-E0011) drop-in for the decisions log

Docs only; no host code changes.

Summary by CodeRabbit

• Documentation

  • Added comprehensive Sprint 5 planning documentation for functions and closures implementation, including increment specifications (A–F), design decision log entries, implementation skills guides, and QA procedures.

• Chores

  • Added sprint kickoff materials and archived sprint prompts for project management and historical reference.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro Plus

Run ID: 530d479c-d57d-40e2-bf05-04306168b74c

📥 Commits

Reviewing files that changed from the base of the PR and between ce07caa and 291a7bf.

📒 Files selected for processing (17)

• .claude/agents/grob-closure-specialist.md
• .claude/commands/sprint-5-a.md
• .claude/commands/sprint-5-b.md
• .claude/commands/sprint-5-c.md
• .claude/commands/sprint-5-d.md
• .claude/commands/sprint-5-e.md
• .claude/commands/sprint-5-f.md
• .claude/skills/emitting-closures-and-upvalues/SKILL.md
• docs/design/_pending/D-318-drop-in.md
• prompts/archive/sprint-5/sprint-5-a.md
• prompts/archive/sprint-5/sprint-5-b.md
• prompts/archive/sprint-5/sprint-5-c.md
• prompts/archive/sprint-5/sprint-5-d.md
• prompts/archive/sprint-5/sprint-5-e.md
• prompts/archive/sprint-5/sprint-5-f.md
• prompts/sprint-5/sprint-5-kickoff.md
• prompts/sprint-5/sprint-5-qa.md

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📝 Walkthrough

Walkthrough

Adds the complete Sprint 5 planning corpus for the Grob language: a D-318 design decision log entry assigning error codes E0008–E0011, a sprint kickoff document, six increment command and archived prompt files (A–F covering call/return, named/default args, lambdas/natives, closures, init state machine/narrowing, and sprint close), a closure-specialist agent brief, a closures/upvalues skill reference, and an external QA brief.

Changes

Sprint 5 Planning Corpus

Layer / File(s)	Summary
D-318 design decision and sprint kickoff docs/design/_pending/D-318-drop-in.md, prompts/sprint-5/sprint-5-kickoff.md	D-318 assigns dedicated error codes E0008–E0011 for named-argument call-site diagnostics; the kickoff records the A–F increment ordering, the closed OpCode enum stance, the §6 map→select correction, and the closure gate rule.
Increment A — fn declarations, call frames, return .claude/commands/sprint-5-a.md, prompts/archive/sprint-5/sprint-5-a.md	Specifies CallFrame stack-base semantics, Return unwinding, the E5901 stack-overflow guard, positional arity/type/return-type diagnostics via E0003–E0005, test routing, and acceptance criteria.
Increment B — named and default arguments .claude/commands/sprint-5-b.md, prompts/archive/sprint-5/sprint-5-b.md	Defines the D-113 positional-then-named calling convention, binding order, E0008–E0011 registration and detection, compiler reorder-and-fill emission with no VM/opcode changes, and the full test matrix including gold-master error pairs.
Increment C — lambdas and natives .claude/commands/sprint-5-c.md, prompts/archive/sprint-5/sprint-5-c.md	Specifies three lambda forms, D-296 category-1–3-only resolution, NativeFunction/RegisterNative machinery, the re-entrant native↔VM callback bridge for filter/select/sort/each, and the §6 map→select mechanical correction.
Increment D — closures, upvalue specialist, and skill .claude/commands/sprint-5-d.md, prompts/archive/sprint-5/sprint-5-d.md, .claude/agents/grob-closure-specialist.md, .claude/skills/emitting-closures-and-upvalues/SKILL.md	Specifies category-4 upvalue capture, Closure runtime object, open→closed upvalue lifecycle closing on Return, transitive and per-call-independent capture, full opcode dispatch requirements, and an optional Opus closure-specialist agent brief with a six-step skill reference.
Increment E — init state machine and narrowing .claude/commands/sprint-5-e.md, prompts/archive/sprint-5/sprint-5-e.md	Defines the VM SlotState tag (Uninitialised→Initialising→Initialised), _startupComplete short-circuit for steady-state GetGlobal, E5902 circular-init RuntimeError, and flow-sensitive T?→T narrowing inside if (x != nil) blocks.
Increment F — sprint close and QA brief .claude/commands/sprint-5-f.md, prompts/archive/sprint-5/sprint-5-f.md, prompts/sprint-5/sprint-5-qa.md	Specifies the functions.grob smoke script requirements, §6 clause coverage verification, the third VM-execution benchmark baseline and two-axis gate, and the external QA brief covering all Sprint 5 verification targets, diagnostic parity checks, and findings-document format.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Poem

Six increments march in a tidy queue,
From CallFrame stack to upvalues born anew.
Open→closed they drift when Return rings,
Each counter independent, per-call things.
No opcodes invented, no parser bent askew —
Just docs all the way down, and they're all quite new! 📜

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title uses the correct Conventional Commits format with 'docs' prefix and includes an appropriate scope '(sprint-5)' followed by a clear, imperative summary describing the multiple documentation additions (Sprint 5 prompts, slash commands, and closures skill).
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch docs/sprint-5-prompts

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud