merge: unify confirm dialog — pure hx-confirm + form[method=dialog]

Eliminates confirmAction() entirely. One code path: all confirmations
go through showConfirm() called by the htmx:confirm interceptor.
14 template files converted to hx-boost + hx-confirm pattern.
Pipeline endpoints updated to exclude HX-Boosted requests from the
HTMX partial path.

# Conflicts:
#	web/src/padelnomics/admin/templates/admin/affiliate_form.html
#	web/src/padelnomics/admin/templates/admin/affiliate_program_form.html
#	web/src/padelnomics/admin/templates/admin/base_admin.html
#	web/src/padelnomics/admin/templates/admin/partials/affiliate_program_results.html
#	web/src/padelnomics/admin/templates/admin/partials/affiliate_row.html

CHANGELOG.md

@@ -19,6 +19,12 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/).
 - **Proxy URL scheme validation in `load_proxy_tiers()`** — URLs in `PROXY_URLS_DATACENTER` / `PROXY_URLS_RESIDENTIAL` that are missing an `http://` or `https://` scheme are now logged as a warning and skipped, rather than being passed through and causing SSL handshake failures or connection errors at request time. Also fixed a missing `http://` prefix in the dev `.env` `PROXY_URLS_DATACENTER` entry.
 
 ### Changed
+- **Unified confirm dialog — pure HTMX `hx-confirm` + `<form method="dialog">`** — eliminated the `confirmAction()` JS function and the duplicate `cloneNode` hack. All confirmation prompts now go through a single `showConfirm()` Promise-based function called by the `htmx:confirm` interceptor. The dialog HTML uses `<form method="dialog">` for native close semantics (`returnValue` is `"ok"` or `"cancel"`), removing the need to clone and replace buttons on every invocation. All 12 Padelnomics call sites converted from `onclick=confirmAction(...)` to `hx-boost="true"` + `hx-confirm="..."` on the submit button. Pipeline trigger endpoints updated to treat `HX-Boosted: true` requests as non-HTMX (returning a redirect rather than an inline partial) so boosted form submissions flow through the normal redirect cycle. Same changes applied to BeanFlows and the quart-saas-boilerplate template.
+  - `web/src/padelnomics/admin/templates/admin/base_admin.html`: replaced dialog `<div>` with `<form method="dialog">`, replaced `confirmAction()` + inline `htmx:confirm` handler with unified `showConfirm()` + single `htmx:confirm` listener
+  - `web/src/padelnomics/admin/pipeline_routes.py`: `pipeline_trigger_extract` and `pipeline_trigger_transform` now exclude `HX-Boosted: true` from the HTMX partial path
+  - 12 templates updated: `pipeline.html`, `partials/pipeline_extractions.html`, `affiliate_form.html`, `affiliate_program_form.html`, `partials/affiliate_program_results.html`, `partials/affiliate_row.html`, `generate_form.html`, `articles.html`, `audience_contacts.html`, `template_detail.html`, `partials/scenario_results.html`
+  - Same changes mirrored to BeanFlows and quart-saas-boilerplate template
+
 - **Per-proxy dead tracking in tiered cycler** — `make_tiered_cycler` now accepts a `proxy_failure_limit` parameter (default 3). Individual proxies that hit the limit are marked dead and permanently skipped by `next_proxy()`. If all proxies in the active tier are dead, `next_proxy()` auto-escalates to the next tier without needing the tier-level threshold. `record_failure(proxy_url)` and `record_success(proxy_url)` accept an optional `proxy_url` argument for per-proxy tracking; callers without `proxy_url` are fully backward-compatible. New `dead_proxy_count()` callable exposed for monitoring.
   - `extract/padelnomics_extract/src/padelnomics_extract/proxy.py`: added per-proxy state (`proxy_failure_counts`, `dead_proxies`), updated `next_proxy`/`record_failure`/`record_success`, added `dead_proxy_count`
   - `extract/padelnomics_extract/src/padelnomics_extract/playtomic_tenants.py`: `_fetch_page_via_cycler` passes `proxy_url` to `record_success`/`record_failure`