fix: note indexing, wikilink creation, current-file tracking, ripgrep error handling, inbox review, tree refresh, and colon-title links

[guitmz]

• Read full note contents during cache parsing so tags and wikilinks after 4 KB are indexed correctly (see benchmark notes below).
• Use a shared unique-path helper when creating a missing note from a wikilink, preventing filename-collision overwrites/corruption.
• Render the "No backlinks" section in inbox review, matching the documented feature.
• Rebuild expanded tree branches recursively on refresh so the sidebar stays visually consistent.
• Treat note titles containing : as valid Grove wikilinks instead of misclassifying them as standard org protocol links.
• Preserve normal handling for real protocol links such as [[https://...]] and [[file:...]].
• Add real current-file tracking for the tree sidebar so the highlighted note follows normal Emacs navigation across Grove files.
• Make backlink lookup fail with a user-facing error when rg is missing or ripgrep execution fails, instead of silently returning an empty result set.
• Preserve normal ripgrep semantics by treating exit code 1 as "no matches" rather than an execution failure.
• Added tests

Benchmark note: I measured the new whole-file parser against the previous 4 KB limited behavior on synthetic org files. The current parser took about 0.47 ms for a 64 KiB note, 6.48 ms for a 1 MiB note, and 33.88 ms for a 5 MiB note. An initial cache refresh across 50 x 1 MiB notes took 328 ms total. Since cache refresh only reparses files whose mtime changed, this keeps the new behaviour affordable while avoiding repeated full-vault cost on unchanged notes.

[jonathanchu]

Great work here @guitmz! I went through the fixes - you fixed a bunch of things I missed! The regression tests are are thorough and so very welcomed, too - this helped me track the fixes here.

Can you rebase this PR before it gets merged? Much appreciated!

[guitmz]

@jonathanchu rebase done :) I was early stages in the process of writing a similar package for myself so I had gone already through some design decisions that made a bit easier to find the things in this PR

[jonathanchu]

Appreciate this! Thank you @guitmz !