docs: sync pure-simdjson version references after v0.1.7 bump

[tazarov]

Summary

PR #48 bumped pure-simdjson v0.1.4 → v0.1.7 and fixed the ci.yml bootstrap pin, but left 13 stale v0.1.4 references in prose. This syncs them.

Strategy

Not a blanket find/replace — the references fall into two categories:

Stays pinned (bumped to v0.1.7):

Site	Why
NOTICE.md ×4	Third-party license attribution. Naming the actually-shipped release, and linking to that tag's LICENSE/NOTICE, is the point of the file.
docs/simd-deployment.md — nesting limit	Version-specific behavioural claim. Verified still accurate: defaultMaxDepth = 1024 in v0.1.7, so "accepts at most 1,023 containers, ErrDepthLimitExceeded at 1,024" holds.

Unpinned (now defers to go.mod):

Site	Change
README.md — opt-in section	Links the module unpinned, notes "version pinned in go.mod"
docs — intro	go.mod named as the authoritative version
docs — automatic bootstrap	Dropped the version adjective
docs — bootstrap guide link	Repointed blob/v0.1.4/ → blob/main/
docs — air-gapped	"artifact matching the go.mod version"
docs — corporate mirror	"assets for the go.mod version"
docs — integrity table	Version dropped; the go.sum checksum claim is version-independent

CHANGELOG.md is deliberately untouched — it is an append-only historical record, and its v0.1.4 reference was accurate when written.

Why unpin rather than bump everything

Bumping all 13 would recreate the recurring problem #49 exists to stop: every future pure-simdjson bump needs the same manual sweep across three files, with nothing to catch a miss. That is exactly how these went stale. Deferring prose to go.mod leaves only the two sites where naming a specific release carries real meaning.

Verification

• grep -rn "v0\.1\.4" --include="*.md" returns nothing outside CHANGELOG.md and .planning/
• Docs-only; no code, no build files. Reflowed edited paragraphs to the file's existing wrap width.

Relates to #49 (the underlying pattern — CI pin derivation — is not addressed here).