docs(hacktober): add open-issues tracker + triage recommendations

[priya-sundaram-dev]

Describe your change:

Follow-up to #15081 (cclauss: "read through the open issues, add an open issues section to the end of our prep document and then make a list of which ones we can close").

Appends an Open issues section to docs/hacktober_2026_prep.md, mirroring the existing PR-tracker checklist notation:

• Snapshot of all 144 open issues (21 bug / 82 enhancement / 23 awaiting triage / 2 help wanted) as a checkable list.
• A Triage recommendations subsection — a first pass at which we can close, grouped by confidence so a maintainer can act on a whole bucket at once:
  • A spam / not-a-real-issue (Sin gravedad #15002)
  • B obsolete — target file removed from the tree (Bug: Inconsistent behavior for missing values in coordinate_compression.py #13226 → coordinate_compression.py no longer exists)
  • C close as fixed/duplicate once the linked PR merges (bug(searches): jump_search raises IndexError for empty list input #15085 ← fix: handle empty input in jump_search #14807, dup fix(searches): jump_search returns -1 for empty list (was IndexError) #15101)
  • D stale feature requests with no implementation PR (≥1yr) — ~24 candidates
  • E likely-already-resolved, verify then close (Container build failed in codespaces #10941/DevContainer setup fails #11812 devcontainer, computer_vision README.md link not working #11841/Misformatted/linked wiki entry in python sorting #11225 doc links)
  • F keep open — real, reproducible, good-first-issue material (8 listed)

Each claim was checked against the current master tree; items depending on something I can't see (e.g. a rebuilt Codespace) are marked verify. Docs-only change. Happy to iterate on the buckets or take a second pass through the remaining awaiting triage items.

• Add an algorithm?
• Fix a bug or typo in an existing algorithm?
• Add or change doctests? -- Note: Please avoid changing both code and tests in a single pull request.
• Documentation change?

Checklist:

• I have read CONTRIBUTING.md.
• This pull request is all my own work -- I have not plagiarized.
• I know that pull requests will not be merged if they fail the automated tests.
• This PR only changes one algorithm file. To ease review, please open separate PRs for separate algorithms.
• All new Python files are placed inside an existing directory.
• All filenames are in all lowercase characters with no spaces or dashes.
• All functions and variable names follow Python naming conventions.
• All function parameters and return values are annotated with Python type hints.
• All functions have doctests that pass the automated testing.
• All new algorithms include at least one URL that points to Wikipedia or another similar explanation.
• If this pull request resolves one or more open issues then the description above includes the issue number(s) with a closing keyword: "Fixes #ISSUE-NUMBER".