refactor: extract the duplicated timespan lookup in cycle.php

[somethingwithproof]

cycle_graphs() and cycle() built the graph timespan with the same three lines. This moves them into cycle_get_timespan() and calls it from both.

Also drops a stray space before a comma at the second call site.

Rebuilt on current develop. The earlier version of this branch predated #27, which had already converted the array syntax, so most of it was redundant and it no longer rebased cleanly.

No behaviour change.

[Copilot]

Pull request overview

This PR modernizes the Cycle plugin’s PHP files by enabling strict typing and updating some legacy syntax to PHP 7.4-era constructs.

Changes:

• Added declare(strict_types=1); across plugin PHP entrypoints.
• Converted some array(...) usages to short array syntax ([...]) and updated prepared-statement parameter arrays accordingly.
• Introduced two .omc/sessions/*.json files (appear to be local tooling artifacts).

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
setup.php	Adds strict typing and updates a couple of arrays to short syntax.
functions.php	Adds strict typing and partially modernizes arrays/params in several functions.
cycle.php	Adds strict typing and updates a few array() initializations / prepared params.
index.php	Adds strict typing to the plugin redirect entrypoint.
images/index.php	Adds strict typing to the redirect stub.
locales/index.php	Adds strict typing to the redirect stub.
locales/LC_MESSAGES/index.php	Adds strict typing to the redirect stub.
.omc/sessions/859688d5-ece7-4d1e-ab13-c82d820e7440.json	New session JSON file (likely unintended).
.omc/sessions/42a5a3ed-3430-434f-addf-dc7423bda6d8.json	New session JSON file (likely unintended).

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[Copilot]

In validate_request_vars(), the $filters structure now mixes short array syntax ([]) with legacy array() in the same literal, which conflicts with the PR goal of using short array syntax across the plugin and makes the block harder to scan. Convert the remaining nested array(...) entries within $filters to [...] for consistency.

[Copilot]

This looks like a tooling/session artifact and not plugin source. Please remove .omc/sessions/*.json from the repository and add an ignore rule (e.g., .omc/ or .omc/sessions/) so local session data is not committed.

Suggested change

	{
	"session_id": "859688d5-ece7-4d1e-ab13-c82d820e7440",
	"ended_at": "2026-04-09T19:59:02.981Z",
	"reason": "other",
	"agents_spawned": 0,
	"agents_completed": 0,
	"modes_used": []
	}

[Copilot]

This looks like a tooling/session artifact and not plugin source. Please remove .omc/sessions/*.json from the repository and add an ignore rule (e.g., .omc/ or .omc/sessions/) so local session data is not committed.

Suggested change

	{
	"session_id": "42a5a3ed-3430-434f-addf-dc7423bda6d8",
	"ended_at": "2026-04-09T20:11:48.000Z",
	"reason": "other",
	"agents_spawned": 0,
	"agents_completed": 0,
	"modes_used": []
	}

[somethingwithproof]

Converted to draft to serialize the stack in this repo. Blocked by #27; will un-draft after that merges to avoid cross-PR merge conflicts.