refactor: safe PHP 7.4 modernization

[somethingwithproof]

This PR adds strict typing, short array syntax, and null coalescing operators across the plugin. Standalone infrastructure files were removed per architectural mandate.

[Copilot]

Pull request overview

This PR modernizes the HMIB plugin’s PHP code by enabling strict typing and updating legacy array syntax to PHP 7.4-friendly constructs across core entrypoints, pollers, SNMP helpers, and locale/template index stubs.

Changes:

• Added declare(strict_types=1); to multiple PHP entrypoints/files.
• Replaced array(...) with short array syntax [...] in various functions (DB calls, config arrays, helpers).
• Introduced two .omc/sessions/*.json files into the repo.

Reviewed changes

Copilot reviewed 13 out of 13 changed files in this pull request and generated 8 comments.

Show a summary per file

File	Description
templates/index.php	Adds strict types declaration.
snmp.php	Adds strict types; converts arrays; introduces invalid is_[...] syntax (parse errors).
snmp_functions.php	Adds strict types declaration.
setup.php	Adds strict types; converts arrays to short syntax.
poller_hmib.php	Converts prepared-statement parameter arrays to short syntax.
poller_graphs.php	Converts prepared-statement parameter arrays and local arrays to short syntax.
locales/LC_MESSAGES/index.php	Adds strict types declaration.
locales/index.php	Adds strict types declaration.
index.php	Adds strict types declaration.
hmib.php	Converts many filter/config arrays to short syntax.
hmib_types.php	Adds strict types; converts arrays; introduces invalid is_[...] / in_[...] syntax (parse errors).
.omc/sessions/df36c0d4-5118-49a8-b66b-5f851e645aa8.json	New tooling/session artifact committed (should not be in source).
.omc/sessions/c0ab85d1-d888-4fad-b941-516cdad3f729.json	New tooling/session artifact committed (should not be in source).

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[somethingwithproof]

Converted to draft to serialize the stack in this repo. Blocked by #40; will un-draft after that merges to avoid cross-PR merge conflicts.

[somethingwithproof]

Verified all 8 Copilot findings against the current diff: the is_[$var]/in_[$var] parse-error patterns they flagged were already fixed by 97b5816 and cde19ce (same PR), and the .omc/sessions/*.json artifacts they flagged are no longer in the tree. Confirmed with php -l on snmp.php and hmib_types.php plus a manual grep for each flagged line. Resolved all 8 threads as stale.

Cherry-picked the CI workflow from #40 (11ffc52, 9e4dbb6) so this branch gets integration test coverage instead of ci=NONE, then hardened it: added permissions: contents: read and pinned actions/checkout and shivammathur/setup-php to commit SHA.

Branch is not behind develop (0 commits).