chore(deps): upgrade pdf-inspector to 0.1.8 (RUSTSEC-2026-0187)

[1688mengdie]

Summary

cargo audit reports RUSTSEC-2026-0187 against the locked lopdf
dependency: a stack overflow when parsing deeply nested PDF objects
(CVSS 7.5). Cargo.lock on main pins lopdf 0.41.0, which is within
the affected range; the advisory is fixed in lopdf >= 0.42.0.

The vulnerable lopdf version is reached through pdf-inspector 0.1.7
on the anydoc document-reading path. An attacker who can supply a
crafted PDF document can trigger unbounded recursion in the parser and
crash the process.

This PR upgrades pdf-inspector from 0.1.7 to 0.1.8, which raises its
lopdf requirement to >= 0.42.0 so the locked resolution leaves the
affected range. Only the locked version and checksum change; the
dependency graph and application sources are unchanged apart from
transitive lockfile re-pinning of getrandom/windows-sys entries that
cargo re-resolves for the new lopdf tree.

Fixes #2586

Type and Areas

Type: dependency

Areas: Rust core dependency

Verification

• cargo check --locked -p bitfun-cli --jobs 4 — passed (0 errors; 19 pre-existing warnings unchanged).
• cargo tree --locked -i lopdf --depth 1 — resolved lopdf v0.42.0 through pdf-inspector v0.1.8.
• cargo deny check advisories (run in a workspace where the advisory is tracked) — reports the vulnerability on the baseline lockfile and clears after this change (advisory solution: upgrade to >= 0.42.0).
• Full workspace build and runtime PDF workflows were not run locally; repository CI remains the cross-platform verification source.

Reviewer Notes

• pdf-inspector 0.1.8 keeps the same 0.1.x compatibility line; lopdf moves 0.41.0 -> 0.42.0 within its declared requirement.
• No UI change, screenshots, migration, or persisted-shape compatibility work is applicable.
• Rollback is the inverse lockfile-only version/checksum change.

Checklist

• This PR is focused and does not include secrets, temporary prompts, generated scratch files, or unrelated artifacts.
• Relevant verification is recorded above, or skipped checks are explained.
• User-facing strings, docs, and locales are updated where applicable. (Not applicable: no user-facing change.)

This is an AI-assisted change.