feat(engram): add DataDirRef type, location suggestions, and presenter helpers

[tonyblu331]

Summary Introduces the foundational types and location-discovery layer for Engram data-directory management (issue #346, PR B1 of B1+B2+B3): - DataDirRef ΓÇö future-proof path type with Resolve(homeDir), plus DefaultDir and DBPath helpers - SuggestLocations ΓÇö ordered, deduplicated candidate list with free-space labels; returns []Location with IsCurrent flag - Platform-specific volume discovery ΓÇö Statfs on Unix, GetDiskFreeSpaceEx on Windows via syscall.NewLazyDLL - FormatDirLine / FormatSpaceWarning ΓÇö presenter helpers for TUI display (no Bubbletea dep) Bug fixed: IsCurrent was incorrectly set on the default location when a custom dir was active. ## Changes | File | Type | Lines | |------|------|-------| | internal/components/engram/env.go + env_test.go | New | +76 | | internal/components/engram/locations.go + test + platform files | New | +239 | | internal/components/engram/presenter.go | New | +25 | | Total | | +340 / budget: 400 Γ£à | ## Test plan - [x] go test ./internal/components/engram/... -run "TestDataDirRef|TestDefault|TestDBPath|TestSuggest|TestBuildLabel" ΓÇö 10 tests, all pass - [x] go build ./... ΓÇö clean build - [x] Full repo go test ./... ΓÇö Γ£à Pass (CI) - [x] E2E cd e2e && ./docker-test.sh (ubuntu / arch / fedora) ΓÇö Γ£à Pass (CI) ## PR Chain ΓÇö Closes #346 | # | PR | Lines | |---|----|-------| | A | #465 | 152 Γ£à | | B1 | this PR | 340 Γ£à | | B2 | #485 | 171 Γ£à | | B3 | #486 | 370 Γ£à | | C | #487 | 33 Γ£à | | D1 | #488 | 282 Γ£à | | D2 | #489 | 340 Γ£à | --- ## CI status (GitHub Actions) Checks: https://github.com/Gentleman-Programming/gentle-ai/pull/484/checks | Gate | Status | |------|--------| | Unit Tests (go test ./...) | Γ£à Pass | | E2E Tests (ubuntu / arch / fedora) | Γ£à Pass | | Issue reference (Closes #346) + status:approved | Γ£à Pass | | PR cognitive load vs main | ΓÜá∩╕Å May fail while #465 is unmerged ΓÇö GitHub diffs the full stack vs main; this PRΓÇÖs own diff is Γëñ400 lines Γ£à | | Exactly one type:* label | ΓÜá∩╕Å Maintainer applies | bash go test ./... cd e2e && ./docker-test.sh ≡ƒñû Generated with Claude Code

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Chain Context (SDD - stacked PRs targeting main)

Field	Value
Chain	Engram data-directory (#346)
Strategy	Stacked branches; each PR opens vs main - upstream typically has no intermediate GitHub base branches, so merge #465 .. #489 in order; branch ancestry carries predecessor commits.
Tracker PR	none (feature-branch tracker not used).
This PR	#484
Base	Gentleman-Programming/gentle-ai main
Cognitive load (GitHub vs main)	+492/-0 = 492 changed lines
CI budget (400-line gate)	EXCEEDS 400 vs main (additions + deletions). CI requires maintainer-applied size:exception, OR retarget this PR to the previous branch once those bases exist upstream so GitHub shows only the slice diff.

The Summary / Changes tables above describe the scoped review unit for this numbered PR. GitHub diff vs main is cumulative while every PR still targets main, so totals grow down-chain even though each PR narrative stays slice-focused.

Merge-order diagram

main -> PR #465 -> [THIS] PR #484 -> PR #485 -> PR #486 -> PR #487 -> PR #488 -> PR #489

Autonomy

• Single numbered deliverable (Summary).
• Line totals above match GitHub Files changed aggregation vs main for this PR head.

[tonyblu331]

👋 Maintainer request: could you please add the `type:feature` label?

Also a note on the size check: this PR is part of a 7-PR chain (A → B1 → B2 → B3 → C → D1 → D2). Because all PRs target `main`, the cognitive-load check counts accumulated diff until each predecessor merges. The per-PR line counts are:

PR	Own lines
A #465	152 ✅
B1 #484	340 ✅
B2 #485	171 ✅
B3 #486	370 ✅
C #487	33 ✅
D1 #488	282 ✅
D2 #489	340 ✅

Each PR's check will turn green as soon as its predecessor merges. All seven are independently within the 400-line budget.

[tonyblu331]

Superseded by the ≤400 LOC chain (no \size:exception).

• CLI / Windows tests: PR test(cli): stabilize cross-platform env and path assertions #490 → \main\ (Closes fix(tests): fallos de tests pre-existentes en entornos Windows #103).
• Engram data-directory: PR feat(storage): cross-platform disk space query and byte formatting #491 (slice 1/9) → \main\ (Closes First-class Engram data-directory selection and migration in install/TUI flows #346); follow-up branches \eat/engram-dd-02-types\ … \eat/engram-dd-08b-app-tui-hardening\ on fork — merge sequentially (see comment on feat(storage): cross-platform disk space query and byte formatting #491).

This draft exceeded the 400-line review budget vs \main.