Add session naming to bootstrap workflow (#227)

* Add session naming to bootstrap workflow and assembled prompts

When a template is selected, the bootstrap engine now sets the
session name to '<Template Name> — <User's Topic>' using the
platform's naming mechanism (report_intent for Copilot CLI,
title-setting for Claude Code).

Assembled raw prompts now include a '# Session Name' section at
the top so target LLMs also set meaningful titles when the prompt
is loaded.

Fixes #201.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Address review: display name, conditional report_intent, assembly ordering, topic fallback

- Session name: clarify 'Template Name' means the display name from
  the '# Task:' heading, not the kebab-case slug.
- report_intent: make conditional ('if available') to avoid prompting
  for non-existent tools.
- Assembly Process: add SESSION NAME as step 1 (non-component
  prelude for raw prompt output only), renumber remaining steps.
- Topic fallback: if no concise topic can be inferred, use just the
  template display name without a trailing dash.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Address review: defer session naming, fix terminology, add fallback example

- Move session naming out of step 3 (template may switch later) into
  step 5a (interactive, template is final) and after step 5b output-
  mode selection (single-shot, template may have switched).
- Add dedicated 'Session Naming' reference section with format rule,
  examples including topic-less fallback, and platform mechanisms.
- Fix assembled prompt example: use 'Template Display Name' (not
  'Template Name'), show optional topic with bracket notation,
  remove parenthetical instruction from Session Name section.
- Assembly Process step 1 (SESSION NAME) already documented.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Address review: remove ambiguous bracket notation, document report_intent call shape

- Assembled prompt: replace bracket notation with explicit two-form
  rule (with topic / without topic) and note not to include brackets
  literally.
- Session Naming section: document report_intent call shape with
  intent parameter and concrete example. Correct API shape (intent
  field, not title field).

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

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Co-authored-by: Alan Jowett <alan.jowett@microsoft.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>