Allow changing instance url

[tomli380576]

No description provided.

[Copilot]

Pull request overview

This PR adds a Snap-specific mechanism to override the Jira instance URL at runtime (via snap set), and surfaces guidance for users in both the UI and documentation.

Changes:

• Add a Snap configure hook to persist a jira-server snap config value and invalidate cached Jira credentials when the server changes.
• Update Snap runtime environment handling so the configured Jira server URL is exported as JIRA_SERVER for app commands.
• Add user-facing instructions in the Jira auth modal and README on how to change/reset the Jira server URL.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/bugit_v2/bug_report_submitters/jira_submitter.py	Shows Snap-only guidance in the Jira auth modal for changing the configured Jira server.
snap/snapcraft.yaml	Documents the override mechanism and ensures the submit app runs with the env wrapper.
snap/local/scripts/env_wrapper.sh	Exports JIRA_SERVER from Snap-persisted configuration when present.
snap/hooks/configure	Implements snap set bugit jira-server=... handling and invalidates cached credentials on change.
README.md	Documents how to set/unset the Jira server URL for the Snap install.

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[Copilot]

Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated no new comments.

Suppressed comments (1)

snap/hooks/configure:27

• The URL sanity-check regex allows values like https://? or https:///path because it doesn't actually require a host portion (despite the comment saying it does). This could lead to storing an unusable Jira server URL and confusing failures at runtime.

    # only a lightweight sanity check: must be an http(s) URL with a host
    # made up of valid URL characters (no whitespace or other invalid
    # chars), not a full validation that it's a real/reachable Jira instance
    if ! printf '%s' "$JIRA_SERVER" | grep -Eq '^https?://[A-Za-z0-9._~:/?#@!$&()*+,;=%-]+$'; then
        echo "jira-server must be a valid URL with no whitespace or invalid characters, e.g. https://your-instance.atlassian.net (got: '$JIRA_SERVER')" >&2